Charge Distribution View: Large Difference in Friction Performance Between Graphene and Hydrogenated Graphene Systems.

Density functional theory calculations including dispersion correction (DFT-D2) were used to investigate the relationship between charge distribution and nanofriction characteristics of graphene-based material systems. In our calculations, the single-side-hydrogenated graphene (SSHGraphene) system exhibits lower coefficient of friction, whereas the graphane system exhibits larger one compared with graphene system. These results are attributed to the adjustments of interfacial charge distribution that are induced by different hydrogen passivations. The charge distribution is smooth along the sliding direction for the SSHGraphene sheet, which yields a small potential barrier. Corrugation of the charge distribution in graphane system is much steeper than that in graphene system, which leads to a larger potential barrier. Comparative investigations reveal that the interfacial charge distributions determine the nanofriction performance, which may be helpful for friction modulation and design of new controlling lubricant material. [ABSTRACT FROM AUTHOR]